SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '884267b35f44b146dde16be1be936ab8c1c963adfda0c1396f2c6077ea7a1067' 
  AND token = '5liRSGJZ1onGff4KBHqonU9WdOF+kruayanZfTOKhaY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}